This invention relates to methods and apparatus for shaping and planing wood products, particularly elongate wood paneling boards.
In the wood products industry there is a demand for elongate boards whose side edges are cut to interlocking shapes so that adjacent sides of adjacent boards will matingly fit together, thereby providing additional strength to a surface constructed from a plurality of such boards for resistance against bending and independent movement of the individual boards. Typically, one side edge of such a board is provided with a protrusion running throughout the length of the board in the center of the edge and the other side edge of the board is provided with a groove likewise running throughout the length of the board in the center of the edge for receiving the protrusion of an adjacent board, which is commonly referred to as "tongue-and-groove" matching. The need for side edge matching is particularly great in the use of interior wall paneling in order to keep the visible surfaces of adjacent board even with one another to achieve an orderly appearance, though the need for such matching also arises in the construction of wood flooring, exterior paneling and the like.
It has long been known how to shape the side edges of boards with matching, interlocking cuts. For example, the apparatus disclosed in Knight U.S. Pat. No. 16,777 cuts interlocking shapes on the two side edges of an elongate board, and planes and sands a face of the board as well. Such a machine may be adjusted to accept a variety of different width boards. Woods U.S. Pat. No. 364,743 likewise discloses a machine for planing a face of a board and cutting matching side edges therein, including powered rollers which move the board entirely through the machine.
Ordinarily during construction of a panelled wall such side-matched boards are cut to a length such that their ends come together at a stud or other supporting structure in order to provide support for those ends. Without such support of the ends, lateral bending of the boards may occur, resulting in an uneven surface and reduced strength thereof. However, the need to bring ends of side-matched boards together at a stud results in wastage of material, since pieces which must be cut off the ends of such boards either in the manufacturing process or in the actual construction of a wall are often too short to be utilized between studs and therefore are discarded. Also, the need to bring board ends together at studs limits the variation in appearance of such walls due to the regularity of joint positions which is caused by bringing ends together at studs, which are typically uniformly spaced.
The aforementioned wastage of wood paneling and uniformity of appearance can be avoided by cutting interlockingly matching shapes in the opposite end edges of such boards as well as in the side edges. That is, one end and an adjacent side may be cut with a tongue shape and the other end and side with a groove shape so that the ends of such board need not necessarily be joined at studs to provide the needed support to avoid lateral bending. By utilizing end matching, boards which are too short to be used between studs may be incorporated in a wall, and boards which are not equal in length to the distance between an integral number of studs may be used without cutting down to the distance between an integral number of studs, thereby avoiding the cutting of more than a very short portion off the end of any board in the construction of a paneling surface such as a wall.
End matching of boards has heretofore been achieved primarily by the use of an apparatus known as a "double-end tenoner" which has two opposing rails for supporting cutting implements to shape edges of a board and a means for feeding boards through the machine between the two rails. In the use of this apparatus to match the ends of paneling boards, the raw boards are first graded according to length and width. Thereafter the double-end tenoner must be adjusted so that the distance between the two cutting rails is equal to the length of the boards to be end-matched, and the cutting apparatus on the rails must be arranged to cut interlockingly matching shapes on opposite ends of the boards. The boards are then fed through the machine laterally one by one to be cut. After the boards are cut on their ends by the double-end tenoner they must then be run longitudinally through a molding machine such as the aforedescribed apparatus to match their side edges and plane their faces. The same process can be achieved in an even less efficient manner by running each edge of the board through a single side shaper and thereafter running the boards through a planer. In either case these procedures are time consuming, complicated and require more than one machine.
Accordingly, there is a need for an apparatus which, in a single operation, cuts interlockingly matching shapes in opposite end and side edges of a board and planes a face thereof. Moreover, such a machine should ideally accept random lengths of board and be adjustable to varying widths.